Furnace-grate.



No. 746,556. PATENTBD DEG. 15, 190s. P. o. ARMSTBAD. PURNAGB GRATE.

LLLLLLLLLLLLLLLLLLLL 23, 1902.

No. 746,666. PATENTED DB6. 15. 1966.

P. 0. ARMSTBAD.

FURNAGE GRATE.

APPLIOATION FILED JULY 23, 1902.

N0 MODEL. 4 SHEETS-SHEET 4.

jl Y W, 712 je im al La attorney.;

UNITED STATES Patented December 15, 1903.

PATENT OEEioE.

FRANK C. ARMSTEAD, OF BROOKLYN, NEW YORK, ASSIGNOR, BY MESNE ASSIGNMENTS, TO THE VESTINGHOUSE MACHINE COMPANY, OF PITTS- BURG, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.v

FU RNACE-GRATE.

SPECIFICATION forming' part of Letters Patent No. 746,656, dated December 15,1903.

Application filed .Tilly 23, 1902. Serial No.1,16,598. KNO model.)

i To @ZZ whom` it may concern: Y

Be it known that I, FRANK O. ARMSTEAD, a citizen of the United States of America, residing at the city of New York, borough of Brooklyn, county of Kings, in the State of New" York, have invented certain new and useful Improvements in Furnace-Grams, of which the following is a specification.

l This invention relates to improvements in 1o grates for furnaces of that class known as inclined grates or those which consist of a series of transversely-arranged grate-bars having horizontal top surfaces to support the fuel and in which said bars are arranged in stepped relation with the front edge of one bar overlapping the rear edge of the subjacent bar and in which devices are provided for giving a rocking or oscillatory movement toV the bars-as illustrated, for instance, in Let- 'ters Patent Nos. 409,304., 409,305, and 409,650, granted to William R. Roney on the th day of August, 1889.

The invention consists in the features hereinafterdescribed and moreparticularly pointed outl in the appended claims.

As illustrated in the accompanying drawings, Figure l is a longitudinal vertical section through the front part of a furnace and a grate therein. Fig. 2 is a face View of one of the grate-bars shown in Fig. 1. Fig. 3 is a plan View of the grate-bar shown in Fig. 2. Fig. 4 is a detailcross-section taken through two adjacent grate-bars on the line indicated 'by 4.4 of Fig. 2, the said grate-bars being shown at an intermediate position of their oscillatory movement. Fig. 5 is a sectional view similar to Fig. 4, showing the relative position of the-two bars when at the extreme limit of theirthrow in one direction. Fig. 6 is a like view showingr the same bars at the, extreme limit of vtheir throw in the opposite direction. Fig.,7 is a sectional view taken on line 77 of Fig. 2. Fig. 8 is adetail longitudinal section of the grate-bars shown` in F1gs.'2 and 3, taken on line 8 8 of Fig. 3. Fig. Y 9 is a longitudinal section taken on line 9 9` of Fig. 3. Fig. 10is a sectional view ot' two grate-bars, generally'like those shown in Figs. y 1 to V9, but differing somewhat in the form of the rear edges of the bars. Figli is a sectional View taken on line 11 11 of Fig. 10, showing the. rear part of the lowerinost member inlongitudinal section and the iront edge of the uppermost bar in front elevation. Fig.

12 is asectional View of two bars diering 55 from those shown in the'preceding figures in respect to the shape of the fuel-supporting surfaces of the bars. Fig. 13 is a like section of two bars, showing still another modification ot' the form thereof. Fig. 14 is a detail View 6o showing in front elevation the outer edge of one of the bars illustrated in Fig. 13.

First referring briefly to the general illustration given in Fig. 1, A indicates ythe front wall of a furnace, and B the dead-plate or plate located at the bottom of the fuel-door of` the furnace over which the fuel passes to the lop of the grate. O indicates one of the inclined sidebearers by which the bars constituting the inclined grate are sustained or 7o supported. D D D indicate the grate-bars, which are arranged in stepped order with the rear edge of each bar overhanging the front edge portion of the next bar below it, so as to give an inclined form to the grate as a whole. EV indicates an inclined actuatingbar through the medium of which oscillatory movement is given to the several grate-bars. Each grate-bar D is provided at its ends with trunnions d d, which rest in bearing-notches 8o vformed in the inclined supporting plates or bearers, one of' which is indicated by O. Each of the bars D consists of two main portions-wiz., a relatively` thin vertically-arranged lower member or web D and a top S5 plate D2, which is secured upon the upper edge of the web and which forms the fuelsupporting surface ofthe bar. The web D is shown as made of skeleton form in order to reduce the weightvof the bar and to facili- 9o tate the passage of air therethrough to the n tire and to permit the introduction of a slicing-bar when necessary. The trunnious d d through which are inserted bolts d3, which pass through vertical apertures in the top plate and in said lugs d and which serve to detachably secure said top plate to the web. The said web D' is also shown as provided with a depending arm or lug d4, which is adapted to engage one of a series of notches c in the actuating-bar-E, whereby endwise reciprocatory motion in the said actuatingbar lis transmitted to the several grate-bars for giving oscillatory or rocking movement thereto. E in Fig. 1 indicates an operatingbar or pitman by which motion is transmitted from suitable grate-actuating devices to the actuating-bar E, said pitman E being pivoted to the bar E by a pivot-pin e'. In the case of a number of bars at the upper part of the grate the notches e are preferably made wider than the ends of the arms d4, which engage the same, while in the case of the bars at the lower part of the grate the said notches c are made about as wide as or only slightly wider than the ends of said arms d4, this construction aording considerable lost motion between the actuating-bar and the grate-bars at the lower part of the grate, so that the latter are oscillated through a less distance than the bars at the lower part of the grate. prevents a too-rapid movement of the fresh or un'burned fuel at the top of the grate, which is liable to move more freely than that which has been partially burned.

So far as above described the grate-bars illustrated in the drawings are generally similar to those shown `in the prior patents granted to William R. Roney, hereinbefore referred to, and in a prior patent, No. 581,061, granted to William W. Churchill April 20, 1897.

The features constituting my invention are embodied in the upper members or top plates of the'grate-bars or the portions thereof upon which rests and by which is supported the fuel, which is delivered to the upper end of the inclined grate and which is carried or moved downwardly over the grate bars through the rocking or oscillatory movement given thereto during the process of combustion.

First referring to the form of construction in the top plate or upper member D2 of the grate-bar, which is illustrated in Figs. l to 9, inclusive, the grate-bar is elevated at its inner and outer margins above its intermediate portion, or, in other words, is curved transversely, so as to give to its fuel-supporting surface a concave or recessed form, and is also provided with transverse ridges, the transversely-curved form of the plate forming between the said ridges a series of cavities, depressions, or pockets. As shown in Figs.v 2,4, 5, 6, 7, 8, and 9, the ridges and deypressions referred to are formed by transversely corrugating the plate, so as to constitute alternate grooves and ridges on both the upper and lower surfaces thereof. Moreover, as shown in said figures, the front edges of This the said top plates are corrugated to correspond substantially with like corrugations on the rear edge of said top plate, While at the intermediate portion of the bar or that which constitutes the fuel-supportin g surface thereof the corrugations are made of considerably greater depth, as more clearly shown in Figs. 4, 5,and 6 and in dotted lines in Fig. 2, thereby forming a plurality of depressions or pockets between the transverse ridges, the same being arranged at equal intervals across the fuel-supporting portion of the bar or that part of the same which is not covered by the overlapping front margin of the next bar above it. As shown in the figures above referred to, the transverse ridges (indicated by d5) are straight, or approximately so, on their upper surfaces,while the bottoms of the intervening depressions are elevated at ltheir rear parts, as indicated by d6, and are also elevated at their forward parts, as indicated by di', but are depressed in their parts indicated by d8 to form the recesses or pockets herein before referred to. The bars having their upper members or top plates shaped as above described are so arranged in the furnace that the trans'- verse ridges and intervening depressions of the several bars come in the same vertical planes, so that the ridges and depressions at the forward edge of one bar correspond in position with and are adapted to fit into the ridges and depressions at the rear edges of the subjacent bar. As a result of this construction when the bars are rocked or moved in a direction to carry their forward edges downwardly and their rear or inner edges upwardly the depending projections on the up# permost bars fit or enter within the depressions of the under or lowermost bars. As illustrated in the accompanying drawings, Fig. 4 shows the two adjacent bars in an in. termediate position of their throw, Fig. 5 shows the same bars with their outer or fuelsupporting margins thrown downwardly and the said margins in contact, or substantially so,with the rear margins of the subjaceut bars, and Fig. 6 shows the position of the adjacent bars when the fuel-supporting margins are thrown upwardly and the bars are most widely separated from each other. As shown in said Figs. l to 9, inclusive, the upper members or top plates of the grate-bars are provided with air passages or openings extending vertically therethrough and located in transverse rows along the elevation or ridges of the bars, these openings, as clearly seen in Fig. 7, being preferably made of tapered form and larger at their lower than4 at their upper ends. Said air passages 0r openings (indicated by 019) are for the purpose of admitting a supply of air to the fuel in excess of or additional to that furnished through the spaces between the overlapping edges of the bars.

An important feature of the grate-bar made as above described is the concaved or recessed form given to the upper or fuel-supporting surface of the bar. One important advantage gained by the recessed or concaved form of the top surface of the bars is that of retaining on the bars layers or masses of ashes from the burning fuel, which ashes by reason of the depression of the bottoms of the recessed parts or pockets of the bars below the forward edges thereof are confined in the said recessed parts or pockets and therein remain, notwithstanding the vibratory movement of the bars. The masses of ashes thus lodged on the bars largelyprevent immediate con tact of the burning fuel with the surface of the bars, and thus greatly facilitates the keeping of the same cool, or, in other words, decreases the liability of the burning out of the bars. Another advantage gained by the presence of said concave parts or depressions is that of retarding the downward movement of the fuel along or over the stepped surface of the inclined grate, especially in the case of fine or granular anthracite coal, it being obvious that the downwardly-moving particles of the coal are more liable to be arrested and temporarily held,

from downward movement by contact with the concave or depressed parts of the gratebars than in the case of a bar having a fiat or substantially vflat top surface.

An important advantageis gained by the presence of the ai r-openings darran ged along vthe elevated parts or ridges of a grate-bar having such ridges, for the reason that these "unprotected by the masses of ashes.

Ageneral advantage gained by making the grate bars of laterally curved or channelv form, as well as by corrugating them transversely, is that a bar of this shape is stronger or stiffer and is less liable to be warped or distorted by heat than would be a straight bar containing the same weight of metal. be especially observed that inasmuch as the front edge of the bar, which directly supports andis most directly exposed to the heat from `the incandescent fuel, is liable in the case of a` straight bar to be expanded by heat, so as to bend the bar into concave form at its rear A:,edge, while in the case of a bar corrugated at its front edge inthe manner shown the action of the heat has no tendency to expand 6o or elongate said front edge of the bar. `More- It will able, because the top plate being secured to the lower part or web of the bar the greater expansion of the said top plate under the greater heat to which it is subjected would result in the warping or bulging of the top plate and in the liability of distortion of the en tire bar.

An advantage gained by corrugating transversely the rear 'or inner, as well as the forward or outer, edges of the bars and so arranging the bars that the ridges and grooves of adjacent bars [it within each other is that this construction affords a greater degree of oscillatory movement in the bars than would be possible if the front edges of the bars were corrugated and the top surfaces of the bars at their rear edges were straight or flat, because in thelatter case the ridges on the lower surfaces of the front edges of the superposed bars would strike the flat rear edges of the subjaceut bars, and thereby limit the movement of both bars.l of vibratory movement is desirable, because giving greater agitation of the fuel, such as is especially desirable in the case of fuels which are liable to coke or cake in the process of combustion. The corrugation of the upper surface of the rear margins of the bars to fit the corrugations of the lower surface of Such greater amplitude IOO the front margins of the bars is also an advantage, because making it possible to limit toa desired extent the passage of air between the bars, it being obvious that if the actuating devices for the bars thus constructed are so adjust-cdas to bring the edges of the bars together the passage of air through the bars IIO at the time they are oscillated forwardly or downwardly will be entirely cut olf and in other positions correspondingly lessened.V

This is a matter of considerable importance in 4the use of ne coal and where a strong IZO of fine fuel, which is liable to be dislodged by the entrance of air-currents of considerable force and volume, by making the contactsur faces of the bars of corrugated form and iu such manner that they interfit when brought into contact witheach other and at the same time providing said air-openings the air-sup ply will be largely afforded by said openings 19, which direct small jets of air upwardly through the fuel, which jets of airdeect upwardly the air entering horizontally between the bars, and thereby afford a suitable airsupply with much less liability of dislodging the fine fuel than in the case when all of the air-enters horizontally between the gratebars.

Figs. 10 and 11 illustrate a construction in the meeting edges of adjacent grate-bars in which both the forward edge of the upper bar and rear edge of the lower bar are corrugated, but in which the corrugations in one part are deeper than those in the other, so that when the overlapping margins are brought together -in the rocking of the bars spaces or openings are still aiforded for the passage of air. A construction of this kind will of course be employed in cases where the entrance of air with considerable force and volume between the grate-bars will not 'be objectionable, it being obvious that this construction will make it impossible for the operator to so adjust the actuating devices of the bars as to entirely close the spaces between the bars,

and thus cut off the supply of air in any position of said bars.

In Fig. 12 is shown a construction slightly different from that illustrated in Figs. 1 to 9 by reason of the fact that the transverse ridges of the corrugated top plate (indicated by d10 in said Fig. 12) are curved to conform to the curvature of the bottom of the depressions or vrecesses between the ridges instead of being straight, as shown, for instance, in Fig. 4.

In Figs. 13 and 14 I have shown a form of grate-bar embodying the main features of my invention wherein the fuelsupporting surface only of the bar is corrugated, while the rear surface of the bar or top plate, which extends beneath the front margin of the superjacent bar, is fiat or uncorrugated. The advantages gained by the provision of depressions or recesses to receive and hold ashes and the benefits derived from giving a corrugated form to the part of the bar most greatly exposed to the heat are the same in this form of bar as in the form of construction hereinbefore described.

An advantage arising from the use of the construction shown in Figs. l to 9, as compared with the prior flat form of top plate will be obvious from consideration of the fact that as the forward edge of the upper bar approaches the fiat surface of the lower bar, these surfaces being approximately parallel with each other, some of the fine fuel which may have fallen on the rear surface of the lower bar may be squeezed or forced out of the space between the bars, and thus fall through the grate. When, however, the bar is concave and its lower surface is inclined upwardly toward the front edge of the bar, as shown in Figs. 4, 5, and 6the rear edge of the lower bar will strike the under surface of the upper bar at the depressed part of said surface, so that a V-shaped opening, Fig. 5, will be left between the adjacent surfaces of the bars, and any fuel caught between the bars will be forced forwardly upon the lower bar and will have no tendency to fall through the space between the bars.

Itis to be understood that my invention is not limited to the specific details of construction shown in the accompanying drawings, but that such details may be varied in the practical carrying out of my invention, as may be found necessary or desirable. It is also to be understood that the features specifically pointed out in the several claims are intended to be separately claimed without limitation to the use in connection therewith of other features and details of construction illustrated.

I claim as my invention- 1. An inclined grate consisting of a plurality of pivorally-mounted grate-bars arranged in stepped and overlapped relation, the upper surfaces of said bars being provided with transverse ridges and the bottoms of the grooves between the saidk ridges being elevated at the outer and inner margins of the bar to form pockets which constitute ash-receiving recesses.

2. A grate having a plurality of pivotally mounted overlapping grate-bars, the upper surfaces of said bars, in their fuel-supporting portions, being provided with transverse ridges and the bottoms of the grooves between said ridges being elevated at the outer and inner margins of the bars and the depressed part of said grooves extending throughout the greater portion of the width of the said fuel-supporting part of the bar to form transversely-elongated pockets which constitute ash-receiving recesses.

3. A grate provided with a plurality of pivotally-mounted, overlapping grate-bars provided on their top surfaces with transverse ridges extending throughout the width thereof, the bottoms of the grooves between said ridges being elevated at the outer and inner margins of the fuel-supporting portion of the bars to form pockets constituting ash-receiving recesses.

4. A grate having a plurality of pivotallymounted, overlapping grate bars provided on their upper surfaces with transverse ridges, the bottoms of the grooves between said ridges being elevated at the outer and inner margins of the bars to form pockets which constitute ash-receiving recesses, said bars having air-supply openings extending through the said ridges.

5. Aninclined grate consisting of pivotallymounted overlapping grate-bars arranged in ,stepped relation, and provided on their upper surfaces with transverse corrugations, forming ridges and intervening grooves, the bottoms of which were elevated at the outer and inner margins of the bars to form pockets which constitute ash-receiving recesses be- IIO IIS

tween the ridges, the lower surfaces of the bars, at their outer edges, being corrugated to correspond with the corrugations at the top surface of the bars and the grooves in the upper surfaces of the bars at the inner edges thereof being deeper than the ridges on the lower surfaces of the superposed bars at the outer edges of the latter.

6. An inclined grate consisting of pivotallymounted, overlapping grate-bars arranged in stepped relation and having top plates which are transversely corrugated, the bottoms of the grooves formed by the corrugations in the top surfaces of the bars being elevated at the outer and inner margins of the bars to form pockets which constitute ash-receiving recesses.

7. A top plate or member for a grate-bar, which is transversely corrugated, and in which the bottoms of the grooves in the cor- FRANK C. ARMSTEAD.

Witnesses:

C. CLARENCE PooLE, WILLIAM R. RoNEY. 

